By virtue of economic advantage, the compatibility for freely shaping final goods, and light weight, molded plastic goods are widely made available for a variety of fields today in an extremely large quantity including the manufacture of automobiles and electric appliances, for example.
Conventionally, plastic goods are manufactured by applying the injection molding process.
However, in recent years, some of those skilled in the art have introduced a system for molding resin by applying such a pressure molding apparatus comprising a molding unit incorporating upper and lower molds 15 and 16 shown in FIG. 2 A though D.
More particularly, a gate pipe 20 for feeding molten resin is disposed beneath the gate aperture 19 provided for the lower mold 16 of the molding unit 17 composed of the upper and lower molds 15 and 16.
This molding unit 17 feeds molten resin 18 stored in the gate pipe 20 from the gate aperture 19 to the interior of the molding unit 17 before pressing and molding it.